A Roof Conflict in the Instruments of Service

The documents conflict three ways and the conflicts are not equivalent. One quarter inch per foot is 2.08%, so the 1/8 in/ft on the plan is half the specified and code-minimum slope - it is not a rounding difference.

Direction: keep the flat slab, which is already placed, and achieve the slope in tapered insulation.

• Issue an ASI with a revised roof plan relocating all 14 drains clear of the screens and adding crickets at the screens, the parapet, and roof-to-wall intersections.
• Require the insulation manufacturer to furnish the tapered layout as delegated design, with the specified R-value met at the drain (the thinnest point), not at the high point - this is where R-value compliance usually fails.
• Check the consequences of 2-4 in. of added perimeter thickness: base flashing height, parapet coping, roof hatch curb, and roof-level mechanical curbs.
• Coordinate with the structural and mechanical engineers before issuing, and give the contractor the layout so the change order is priced from a real quantity rather than a contingency.

Issue the ASI first to stop the schedule clock; price it second. Holding the directive until cost is agreed is how a design conflict becomes a delay claim.

The conflict is between the architect's own drawings and specification, not a means-and-methods question or a contractor error. Under standard owner-architect and owner-contractor terms, the contractor is entitled to the change order for the actual added cost - tapered insulation, crickets, drain relocation - and to time if the affected work is on the critical path. The two-week claim must be tested against the actual affected sequence, not accepted as stated.

Owner-facing: disclose promptly and in writing what happened and what it costs. Silence during a negotiation is what turns a $40,000 problem into a liability dispute.

Internal:

• Notify the professional liability carrier as the policy requires - most policies require notice of circumstances, not only of claims.
• Confirm the deductible and any waiver of consequential damages in the owner agreement.
• Keep the file factual; state the conflict and the correction, and avoid admissions of fault in correspondence.
• Log the event in the QA system and check whether the same detail appears on other active projects.

Root cause: the roof plan and the roof specification were produced by different people and nobody compared the slope on the plan against the spec, the structure, and the manufacturer's requirements. The structural drawing showing a flat slab with no crickets was the last chance to catch it and was never cross-checked.

Prevention:

• One roof-system control sheet listing slope, R-value, drains, crickets, parapet height, flashing heights, and warranty requirements, signed by a single responsible person.
• Discipline coordination reviews keyed to a short list of high-risk assemblies - roofing, waterproofing, fire-rated penetrations, curtain wall - at 60%, 90%, and 100%, rather than a general instruction to check the set.
• Author-draws-it rule: whoever writes a specification section draws or redlines the corresponding plan condition.
• Red-team review by someone outside the team, using the RFI logs from past projects as the checklist.
• Track coordination items to zero before permit issuance; an open item on the log is a future change order with your name on it.